This invention relates generally to video signal distribution systems. In particular, this invention relates to systems for distributing video signals from video signal sources to selected locations in a home and for controlling the video signal sources from any television set in the home. Still more particularly, this invention relates to systems for distributing throughout a home broadband signals from sources such as antennas or cables and locally created video signals from sources such as VCRs, videodisc players and satellite receivers.
Modern consumer electronics brings a wide array of video signal choices to the consumer. Video appliances such as VCRs, satellite receivers., and videodisc players are used to augment CATV or antenna service to a home. These video appliances usually connect to television sets in one of two ways. The most common is for the consumer to route his CATV or antenna signal through the appliance and then on to the TV via coaxial cable. A transfer switch inside the appliance will select either the broadband input or the internal channel 3/4 modulator to be connected to the TV. The other common method is to use the baseband video and audio outputs of the appliance and connect to corresponding inputs on the TV.
There are aspects of modern life that are ignored in these schemes. Many homes have more than one video appliance. Connecting more than one video appliance to a TV is not a straightforward matter. Additionally, most homes in the United States have more than one TV.
For years a small marketplace of video accessories has existed to distribute either the baseband video/audio or the channel 3 RF from multiple appliances to several TVs. These video accessories typically suffer from two problems. One problem is that the selector boxes are often confusing to use. The consumer must select the video appliance from the switch box, be sure that the video appliance has its ANT/VCR switch in the proper position, and turn the TV to channel 3. The selection of appliance often will be different in the room where the appliances are located. The second problem that switch boxes do not address is the need for control of the appliances at the remote television. There is a secondary market of IR signal repeating devices that will accept IR control signals in one room of a house and transmit them via wires or radio waves to a second device positioned near the appliances. These signals are turned into IR pulses that duplicate the originals, which allows the consumer to start and stop the VCR, or to change satellite channels.
Devices exist that address these problems in a unified fashion. For years professional satellite installers have been installing external video modulators to these appliances. These modulators have channel assignments that are programmable by the installer. Correct use of these devices would remove switches entirely from this system, and instead would create new TV channels where there were none. In a typical house, coaxial cable from all TVs is run to a central location. The broadband CATV (antenna) signal is then split to all of the TVs in the house and amplified if needed. The broadband signal is also combined with new channels that contain the video programming from the VCR and other video appliances. Any TV in the house can watch the broadcast channels normally, or watch the VCR by tuning to the VCR channel (or videodisc player, or satellite receiver). A properly installed system preserves the quality of all signals while greatly enhancing the convenience of use.
Also available with this type of system are add-on accessories that allow IR control signals to be transmitted along the coax cable that provides the programming. The major disadvantage of this system is the expense. These systems are all custom and professionally installed.